PHOTOTYPE PLATES NOS. IX. AND X. 19 



PLATE IX. 



MADREPORE LAGOON, PORT DENISON. 



The scene of this illustration is in close vicinity to that of the Madrepore islet that forms 

 the subject of Plate V., No. i. Throughout its extensive area, it presents an almost uniform 

 growth of Madrepora convcxa. Here and there, however, may be recognised the expanded 

 foliaceous growths of a Montipora, nearly resembling M. cxpansa, and the more shrubby coralla 

 of Madrepora decipiens. The shadowy, half-tone presentments of the totally submerged corals 

 constitute a specially artistic feature in the original negative of this reef-view ; but it is scarcely 

 conspicuous in the reproduction. From a practical standpoint, this calm lagoon is worthy of 

 notice, since it represents a typical example of those areas which abound among the reefs, and 

 are particularly adapted for the artificial culture of mother-of-pearl shell, sponges, and other 

 marine products of commercial value. The facility of access to this lagoon, and to innumerable 

 others like it, from the port of Bowen, merits attention. 



PLATE X. 



NO. 1. -SUBMERGED MILLEPORA, PfiLM ISLANDS REEF. 



The situation of this reef-view corresponds very nearly with that of Plate \T., No. 2. Its 

 most noteworthy feature is the luxuriant growth of Millcpora raiiiosa, visible in dense bush-like 

 clumps immediately beneath the surface of the water, and for the most part rising from a 

 depth of two or three fathoms. It represents the only area, with the exception of Port Denison, 

 Plate VII., in which this Hydroid Coral has been found by the author to enter conspicuously 

 into the composition of the Great Barrier Reef. This species may be readily distinguished from 

 its Port Denison congener by the more slender, cylindrical, contour of its closely-crowded rami- 

 fications, and by its thick, bush-like habit of growth, as compared with the compressed palmate 

 growth-plan of Millepora alcicornis. 



Alcyonaria, of two specific varieties, including Akyoninin glamum and A. flcxibilc, float loosely 

 in the water to the extreme left, while immediately above them may be observed the irregularly- 

 shaped corallum of a Goniastr^a, into whose eroded base a number of Frilled Clams, Tridacna 

 compressa, have wedged themselves, securing a firm anchorage. Among the variety of species 

 scattered over the exposed surface of this reef there is one conspicuous type that has not 

 yet been noticed. This specimen, which looks much like a spheroidal astraeid with abnor- 

 mally large polyp-centres, is situated on the farther margin of the reef, a little to the right of 

 the precise centre. It is, as a matter of fact, an example of the dark-indian, or brick-red, species 



of Mussa, M. corymbosa, illustrated in Chromo plate No. V. A second, commoner, green or 



I) 2 



